Background: Outcomes of cryoballoon ablation for paroxysmal atrial fibrillation (PAF) have been reported in the Western countries but not in Japan. The CRYO-Japan PMS study was a single-arm, observational, multicenter, prospective study of the 2nd-generation cryoballoon Arctic Front Advance(TM). We evaluated device- and procedure-related complications and clinical outcomes at 6 months.
Methods and results: The 616 patients (male, 72%; mean age, 63±11 years) were enrolled from 33 Japanese hospitals. Of all patients, 610 had PAF, and procedural data were analyzed in 607. A subset of 328 patients was followed for 6 months for the primary efficacy analysis. AF recurrence outside the 3-month blanking period or repeat ablation was considered treatment failure. Pulmonary vein isolation was achieved in 606/607 patients (99.8%); 1 patient (0.3%) had a repeat ablation during the blanking period. Freedom from AF at 6 months was 88.4% (95% CI: 84.1-91.6%). Device- and/or procedure-related adverse events included phrenic nerve injury unresolved at hospital discharge in 9/616 patients (1.5%), which resolved within 6 months in 7, pericardial effusion in 5/616 (0.8%), and tamponade in 4/616 (0.6%). One non-device-related death from pneumonia was reported 6 days post-procedure.
Conclusions: Cryoballoon ablation is safe and effective for Japanese PAF patients, with 88.4% AF freedom at 6 months post-ablation. (Circ J 2016; 80: 1744-1749).